kselftest: arm64: fake_sigreturn_bad_size_for_magic0

// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright (C) 2019 ARM Limited

 *

 * Place a fake sigframe on the stack including a badly sized terminator

 * record: on sigreturn Kernel must spot this attempt and the test case

 * is expected to be terminated via SEGV.

 */

#include <signal.h>

#include <ucontext.h>

#include "test_signals_utils.h"

#include "testcases.h"

struct fake_sigframe sf;

static int fake_sigreturn_bad_size_for_magic0_run(struct tdescr *td,

						  siginfo_t *si, ucontext_t *uc)

{

	struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head;

	/* just to fill the ucontext_t with something real */

	if (!get_current_context(td, &sf.uc))

		return 1;

	/* at least HDR_SZ for the badly sized terminator. */

	head = get_starting_head(shead, HDR_SZ, GET_SF_RESV_SIZE(sf), NULL);

	if (!head)

		return 0;

	head->magic = 0;

	head->size = HDR_SZ;

	ASSERT_BAD_CONTEXT(&sf.uc);

	fake_sigreturn(&sf, sizeof(sf), 0);

	return 1;

}

struct tdescr tde = {

		.name = "FAKE_SIGRETURN_BAD_SIZE_FOR_TERMINATOR",

		.descr = "Trigger a sigreturn using non-zero size terminator",

		.sig_ok = SIGSEGV,

		.timeout = 3,

		.run = fake_sigreturn_bad_size_for_magic0_run,

};